Continuous web printing permits economical, high-speed, high-volume print reproduction. In this type of printing, a continuous web of paper or other substrate material is fed past one or more printing subsystems that form images by applying one or more colorants onto the substrate surface. This type of printing has a number of advantages over conventional web printing methods. In a conventional web-fed rotary press, for example, a web substrate is fed through one or more impression cylinders that perform contact printing, transferring ink from an imaging roller onto the web in a continuous manner. These earlier contact printing systems tend to have heavy frame structures, precision-designed components, and complex and costly alignment procedures for precisely adjusting substrate transport between components and subsystems. For this reason, conventional contact-printing systems generally have fixed configurations, with equipment designs that are specific for a restricted range of printing applications and relatively narrow range of media and ink types.
With recent advances in inkjet printing technology, non-contact printing has demonstrated capabilities for high-speed continuous web printing with suitable image quality and provides a range of features that support improvements in equipment flexibility, adaptability, and efficiency. These techniques are disclosed in U.S. Patent Application Publication 2011/0128337 entitled “Media Transport System For Non-Contact Printing”, by Muir et al. Using digitally controlled print-heads that direct fine dots of ink across an air gap and onto the rapidly moving print media, non-contact printing offers a number of advantages not available with these earlier contact-printing systems. Because impression rollers with attached printing plates are not used with these systems, the design of such systems permits more flexibility than was previously available in terms of colorants and other liquids that can be applied, operating speeds, permitted media types, sizes, print formats, and other attributes. In addition, because print content is not transferred from a contacting roller, the printing format/layout of a non-contact digital printing is not limited by an impression roller diameter.
As non-contact printing systems are being developed, a number of design advantages present themselves, including interchangeability of components and modular design. Modular design permits a printing system to be configured or re-configured from a set of standard components, so that the same basic printing system can have a number of different configurations. These techniques are disclosed in U.S. Patent Application Publication 2011/0128338 entitled “Modular Media Transport System”, by DeCook et al. Techniques for web media handling between modules, such as “kinematic” or “exact constraint” mechanical interfaces simplify the task of aligning the media path between one modular component and another. The design of the present invention is well suited to take advantage of systems that make use of exact constraint web handling that make it feasible to re-configure a modular arrangement in a timely and economical manner.
Conventional solutions for adapting a printer to a particular print job or set of printing conditions include feedback loops and similar control arrangements, often with the help of pre-defined “job ticket” parameter sets or templates that can be selectable for a particular print job. These conventional approaches can work well with dedicated and smaller-scale print apparatus that have a narrow range of capabilities and where interoperability of modular components is not needed. Such conventional solutions, however, can fall far short of what is needed in order to support high-speed modular web media printing systems. Some factors affecting interoperability for a modular system can include differences in acceptable media transport speed for various modules; drying time requirements; response time needed at different modules for changing speed or other parameters; environmental factors such as heat and humidity that can affect applied inks and media handling, receptivity, and drying time; colorant density and number of inks or other colorants or fluids used by a job; data processing speeds, media types and properties; and other factors. In a large-scale printing system that is designed to handle different types of print jobs, the number of operational factors that can be varied and possible combinations of parameters that can be used can well exceed the practical limits of pre-defined template parameter sets and exceed the capabilities of interactive control loops or other conventional mechanisms for adapting and interoperability between components.
In order to meet the needs of a dynamic printing market, high-speed non-contact digital printers must provide the capability to be configurable from modular components, and the various capabilities and performance of each modular component must be taken into account at a system level. Thus, there is a need for apparatus and methods that permits modular system configuration and that adapt system operational control to the combined capabilities of the individual modular components.